Deprecate JsonUtils and remove implementation

The code for the prettyPrint method comes from Stackoverflow, which has a license incompatible with our Apache licensed code. The Stackoverflow code has been removed and the method/class deprecated for removal. On the off chance this API is used, I did not delete the whole class in a patch release. Though it was always intended to be an internal class, it was not clearly marked as such.

The effect of this is that the `HttpSender.Request` class' `toString` will no longer be pretty-printed for JSON requests. This is an acceptable compromise for now rather than coming up with an original implementation for non-critical functionality.

See gh-2762

micrometer-core/src/main/java/io/micrometer/core/instrument/util/JsonUtils.java

@@ -15,73 +15,22 @@
  */
 package io.micrometer.core.instrument.util;
 
+/**
+ * @deprecated this will be removed and should not be used
+ */
+@Deprecated
 public final class JsonUtils {
 
     private JsonUtils() {
     }
 
     /**
-     * Based on https://stackoverflow.com/a/49564514/510017
-     *
      * @param unformattedJsonString JSON string that has not been formatted at all.
-     * @return A best-effort at pretty printed JSON, even for malformed JSON.
+     * @return the input string unchanged
+     * @deprecated this will be removed and no longer does anything meaningful
      */
+    @Deprecated
     public static String prettyPrint(String unformattedJsonString) {
-        StringBuilder sb = new StringBuilder();
-        int indentLevel = 0;
-        boolean inQuote = false;
-        for (char charFromUnformattedJson : unformattedJsonString.toCharArray()) {
-            switch (charFromUnformattedJson) {
-                case '"':
-                    // switch the quoting status
-                    inQuote = !inQuote;
-                    sb.append(charFromUnformattedJson);
-                    break;
-                case ' ':
-                    // For space: ignore the space if it is not being quoted.
-                    if (inQuote) {
-                        sb.append(charFromUnformattedJson);
-                    }
-                    break;
-                case '{':
-                case '[':
-                    // Starting a new block: increase the indent level
-                    sb.append(charFromUnformattedJson);
-                    indentLevel++;
-                    appendIndentedNewLine(indentLevel, sb);
-                    break;
-                case '}':
-                case ']':
-                    // Ending a new block; decrese the indent level
-                    indentLevel--;
-                    appendIndentedNewLine(indentLevel, sb);
-                    sb.append(charFromUnformattedJson);
-                    break;
-                case ',':
-                    // Ending a json item; create a new line after
-                    sb.append(charFromUnformattedJson);
-                    if (!inQuote) {
-                        appendIndentedNewLine(indentLevel, sb);
-                    }
-                    break;
-                default:
-                    sb.append(charFromUnformattedJson);
-            }
-        }
-        return sb.toString();
-    }
-
-    /**
-     * Print a new line with indention at the beginning of the new line.
-     *
-     * @param indentLevel
-     * @param stringBuilder
-     */
-    private static void appendIndentedNewLine(int indentLevel, StringBuilder stringBuilder) {
-        stringBuilder.append("\n");
-        for (int i = 0; i < indentLevel; i++) {
-            // Assuming indention using 2 spaces
-            stringBuilder.append("  ");
-        }
+        return unformattedJsonString;
     }
 }

micrometer-core/src/main/java/io/micrometer/core/ipc/http/HttpSender.java

@@ -15,7 +15,6 @@
  */
 package io.micrometer.core.ipc.http;
 
-import io.micrometer.core.instrument.util.JsonUtils;
 import io.micrometer.core.instrument.util.StringUtils;
 import io.micrometer.core.lang.Nullable;
 
@@ -111,8 +110,6 @@ public String toString() {
                     .append(url.toString()).append("\n");
             if (entity.length == 0) {
                 printed.append("<no request body>");
-            } else if ("application/json".equals(requestHeaders.get("Content-Type"))) {
-                printed.append(JsonUtils.prettyPrint(new String(entity)));
             } else {
                 printed.append(new String(entity));
             }